Bacteriostatic composition for salmonellae

ABSTRACT

Provided is a bacteriostatic composition for salmonellae containing, as the active ingredient, a fermented broth obtained by effecting fermentation with the use of a lactic acid bacteriium belonging to the genus Leuconostoc, Streptococcus or Streptobacterium in a sucrose-containing medium, or a preparation originating in the supernatant obtained by subjecting the fermented broth to fractional precipitation from a water-miscible organic solvent.

This application is a 371 application of PCT/JP99/06574 filed Nov. 25,1999.

TECHNICAL FIELD

This invention relates to a bacteriostatic composition for salmonellaecontaining, as the active ingredient, a component originating in thefermented broth of a lactic acid bacterium. More specifically, theinvention relates to a composition utilizable as a feed additive, or amedicine or a health food for prophylaxis or treatment a ofsalmonellosis.

BACKGROUND ART

Some of animals are infected with salmonella when they are infantsshortly after their birth, or even after they have grown to adults, dueto change of the environment, etc. For preventing this, prophylaxis byadministration of antibiotics, vaccines, various viable cell agents [forexample, a product obtained by growth of a strain belonging to the genusStreptococcus or Lactobacillus, competitive exclusion of salmonellae (CEagent)] or the like, mannose (a kind of sugar) aggregating pathogens andinhibiting their adhesion to the intestinal wall, or oligosaccharides,etc. as health food has been tried.

However, among these methods, antibiotics have the problems, for examplethat resistant strains are liable to occur, the normal bacterial floraadvantageously acting on the living body is also excluded, and there isthe possibility of movement and remaining of : the antibiotics inprocessed stock farm products (“Remaining of feed additives into stockfarm products”, Chikusan Handbook (Stock Raising Handbook), edited byKentaro HIMENO et al., Kodansha Co., 1984, pp. 484-485).

Vaccines have the problems, for example that they are effective only onparticular pathogens, and their effects last only for a limited period(“Nihon no Chikusangyo” (The Livestock Industry of Japan), The LatestData Bank Predicting the Stock Raising of Japan, Chikusan Shuppan Co.,1989, pp. 21-35).

As to various viable cell agents, some of them need storage in a coolplace, they are short in storage time and expensive, and it has beennecessary to administer a large amount of a viable cell agent to animalshaving an established intestinal bacterial flora.

Mannan oligosaccharides aggregating pathogens and inhibiting theiradhesion to the intestinal wall aggregate 48% of pathogenic salmonellaeand inhibiting their adhesion to the intestinal wall, but are noteffective on the residual pathogenic salmonellae, and has the problem[Mikio SHIMIZU, Characteristics and Usefulness of MannanOligosaccharides, “Yokei no Tomo” (Friend in chicken Raising), No. 6,14-18 (1996)].

It is said that oligosaccharides promote the growth of bifid bacteriainhabiting the large intestine of animals and forming the intestinalbacterial flora together with other bacteria, and have asalmonellae-inhibiting effect, but they are expensive and, moreover,uncertain in the effect [for example, Tsuneo FUKADA et al., Onsalmonella infection-inhibiting effect of oligosaccharides in chickens,“Keibyo Kenpo” (Research Paper on Chicken Diseases) 31, 113-117 (1995)].

Further, these antibiotics, vaccines, various viable cell agents, andoligosaccharides such as mannan oligosaccharides aggregating pathogensand inhibiting their adhesion to the intestinal wall themselves do notcontain any perfume components liked by animals, and some of them rathersmell disliked by animals and are unfit as feed additives.

As stated above, prior art exerts certain action and effect on theobject of salmonellae inhibition, but some of them give out a foulsmell, and they themselves do not show an action to enhance animal'staste. Therefore, when they are used for example as feed additives, ithas been difficult to increase the feed intake of animals and improvetheir physical condition.

Thus the object of the invention lies in providing a composition havinga salmonella-inhibiting effect and, in addition, can increase animal'staste.

DISCLOSURE OF INVENTION

The present inventors have intensely studied for providing a compositioncapable of improving or obviating drawbacks following prior art, namelya composition which is effective for prophylaxis or treatment ofsalmonellae infection and can increase animal's taste. As a result, theyfound that a preparation originating in fermented broth with the use ofa certain bacterium belonging to lactic acid bacteria can accomplish theobject and completed the invention.

Thus according to the invention is provided a bacteriostatic compositionfor salmonellae containing, as the active ingredient, a preparationoriginating in a fermented broth obtained by effecting fermentation withthe use of at least one strain belonging to lactic acid bacteriaselected from the group consisting of the genera Leuconostoc,Streptococcus and Streptobacterium in a sucrose-containig nutrientmedium.

Further, as another embodiment, there is provided a method forprophylaxis or treatment of salmonellosis comprising administering thepreparation originating in the fermented broth to a test animal in anamount effective for prophylaxis or treatment of salmonellosis.

Still further, as another embodiment, there is also provided use of thepreparation originating in the fermented broth as an active ingredientfor preparing a composition for prophylaxis or treatment ofsalmonellosis of animals.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a chromatogram of the preparation according to the inventionobtained in Example 1 which chromatogram was obtained under thedescribed operation condition of liquid chromatography.

PREFERRED EMBODIMENTS FOR CARRYING OUT INVENTION

Lactic acid bacteria used in the fermentation according to the inventionmay be any bacteria belonging to the above genera, as long as theyanswer the object of the invention, and as specific ones, there can bementioned Leuconostoc mesenteroides, Leuconostoc dextranicum,Streptococcus bovis, Streptococcus mutans, Streptococcus sanguis andStreptobacterium dextranicum. Preferred bacteria among them areLeuconostoc mesenteroides and Streptococcus bovis. Further asparticularly preferred bacterium, there can be mentioned Leuconostocmesenteroides used for production of dextran. As usable specificstrains, there can, for example, be mentioned Leuconostoc mesenteroidesATCC 10830 (NRRL B-512), Leuconostoc dextranicum ATCC 19255 (NRRLB-3469), Streptococcus bovis ATCC 33317 (NCDO 597), Streptococcus mutansATCC 25175 (NCTC 10449), Streptococcus sanguis ATCC 10556 andStreptobacterium dextranicum ATCC 13134 (NRRL B-1254) available fromAmerican Type Culture Collection (ATCC). Further as to the abovebacteria, when plural bacteria do not mutually influence badly theirgrowth and physical functions, plural bacteria can be used together, butusually, it is suitable to use one bacterium.

The sucrose-containing nutrient medium for fermenting the bacteriumcontains, as a sucrose source, sucrose in an isolated form, or thesqueezed residue of sugar-cane or sugar beet containing sucrose as acomponent, or molasses, beet pulp, bagasse or the like as a by-productformed when sugar is manufactured from sugar-cane or sugar beet. Ascomponents other than sucrose added to the medium, there can bementioned substances or compounds substantially non-toxic on animals,for example, beer yeast extract, peptone, corn steep liquor, soybeanprotein, table salt, HCl, K₂HPO₄, etc.

The fermentation according to the invention can usually be carried outby sterilizing the medium, inoculating a suitable lactic acid bacterium,and conducting culture at around 25° C. under an anaerobic condition.The culture time is not limited since it varies depending on thebacterium used, temperature or medium composition, but it is at leastneeded to choose time of from the logarithmic phase to the stationaryphase. The reason is that when the culture time is too short, there is apossibility that a composition having only a low salmonella effect onanimals is brought about.

Thus, a fermented broth is obtained, and the bacteriostatic compositionfor salmonellae of the invention contains as the active ingredient thefermented broth itself or the supernatant itself obtained by subjectingthe fermented broth, for example to fractional precipitation using awater-miscible organic solvent or a preparation originating in thesupernatant. Thus, the preparation of the invention includes thefermented broth itself or a concentrate of the supernatant originatingin the fermented broth, the later-described cell-free product,spray-dried product or freeze-dried product, etc. It is usually suitableto obtain the supernatant by fractional precipitation, and as theorganic solvent used in the fractional precipitation, there can bementioned ethanol, methanol, acetone, isopropyl alcohol etc. The amountof the used organic solvent based on the broth in the fractionalprecipitation treatment varies with respect to its optimum amountdepending on the kind of the solvent used, but when ethanol is used, theorganic solvent is usually used in an amount of 0.7 to 4 volume partsper 1 volume part of the broth. The treatment temperature is 15 to 35°C., preferably the ambient temperature.

A bacteriostatic composition for salmonellae containing a preparationobtained by removing the cells from the fermented broth, before or afterthe fractional precipitation treatment or simultaneously therewith isalso provided by the invention. The removal of the cells can be carriedout by filtration or centrifugation. The thus obtained preparation canconveniently used when utilized in medicine or health food, but alsowhen used as a feed additive, the preparation is preferred in the pointof easiness of use (for example, homogeneous compounding of the activeingredient is easy, etc.).

As understood from the above, the preparation originating in thesupernatant used as the active ingredient in the composition of theinvention can be used as the form of a purified concentrate obtained byconcentrating a dextran fermentation by-product, which has beendiscarded or left without utilization as a by-product in the preparationof dextran, into 7 to 17-fold, as it is or if necessary after removingthe cells, subjecting to desalting and removing the organic solvent.Thus, the preparation can be prepared extremely inexpensively. Suchsupernatant can be provided in a state of substantially not containingdextran depending on the kind or use amount of the organic solvent used,but such supernatant can also accomplish the desired object of theinvention.

According to the invention is provided, for example, a liquid medicineobtained by merely dissolving the above preparation in a liquid or syrup(concentrate) state in water or physiological saline, or a compositionobtained by compounding the preparation into pharmaceutical excipientsor carriers, or raw materials for feed. There can also be provided as asolid composition obtained by compounding the liquid or syruppreparation into a granulating or solidifying agent commonly used in thepharmaceutical field or the feed field, for example granular glucose,silicic anhydride, cereal grain lees, bread crumbs, soybean cake, bran,cacao bean shells or the like. As to the solid composition, it is alsopossible to prepare the bacteriostatic composition for salmonellae ofthe invention in a solid state by freeze-drying or spray-drying theliquid or syrup preparation, or mixing the thus prepared dry matter withthe above granulating agent or other excipients commonly used in thepharmaceutical or feed field. As the methods for the above preparation,compounding and mixing, methods therefor known per se can be used inaccordance with the dosage forms.

In the invention it is surmised that the desired effect can beaccomplished by the following action mechanism, although not limitedthereto. When the lactic acid bacterium is inoculated into asucrose-containing composition and cultured, glucose among glucose andfructose as the component sugars of sucrose polymerizes into dextran,and, on the other hand, fructose is produced, but in some occasion, thefructose exists in the form of oligo- or poly-fructose as a result ofpolymerization by the action of fructosyltransferase. In addition,various substances including lactic acid and perfume substances areproduced from the bacterium, and therefore, a fermented broth comprisingmany components probably containing lactic acid, fructose, mannitol,leucrose, cells of the lactic acid bacterium used for the fermentation,and other components is formed. Since it is surmised that even afterthis fermented broth is subjected to the fractional precipitationtreatment with the organic solvent as mentioned above, the supernatantfraction contains lactic acid, perfume components, fructose, mannitol,leucrose, dextran, oligo- or poly-fructose, and other culture brothcomponents, and in some occasion, cels of the lactic acid bacterium usedfor the fermentation, the fermented broth can conveniently be used forproviding the preparation of the invention. And it is surmised that bycombination of these components, the preparation is harmless andenhances the taste of animals, and increases the physical condition ofanimals by its lowering effect of the pH of cecum dung, its inhibitoryeffect of invasion of the intestinal mucosa and its inhibitory effect ofsalmonella fixation in the salmonella attack test on chickens, and itsaction of inhibition of mortality and lowering of droppings pH, andexerts excellent effect in production of salmonellae-free hen's eggs,meat and cow's milk.

The use ratio of the preparation contained as the active ingredient inthe bacteriostatic composition for salmonellae of the invention cannotbe limited because the optimum amount is varied depending on its useobject, for example, depending on use for medicine, health food or feedadditives, but a person concerned will be able to determine it referringto the action and effect described in the later-described examples.Generally, when for example as a feed additive for formula feeds, aconcentrate obtained by concentration of up to 12-fold is used, it canbe incorporated so as to be 0.01 to 10.0% by weight, preferably 0.05 to5.0% by weight based on the whole weight of the composition.

Such bacteriostatic composition for salmonellae can be utilizedeffectively for prophylaxis or treatment of salmonella infection orfurther for increase of feed take amount in poultry such as chickens andturkeys, livestock or pets such as cattle, horses, pigs, dogs and cats,and, in addition, humans.

The bacteriostatic composition for salmonellae of the invention isfurther specifically described bellow by examples, but the invention isnot limited thereto.

EXAMPLE 1 Preparation of a Concentrate of the Supernatant in the CaseWhere Sucrose is Used as a Main Raw Material

Leuconostoc mesenteroides ATCC 10830 (NRRL B-512) as a lactic acidbacterium was inoculated into a medium of the following compositioncontaining sucrose as a main raw material, and fermented at 25° C. for24 hours under an anaerobic condition, and then 1 volume of ethanol wasadded to 1 volume of the fermented broth and the supernatant wascollected. The supernatant was filtered to remove the cells, ethanol wasdistilled off at about 80° C. under reduced pressure (540-580 mmHg), andconcentration was carried out so that the liquid amount got to be about{fraction (1/12)} to prepare a concentrate of the supernatant. Theproperties and state and liquid chromatogram (see FIG. 1) of theconcentrate prepared were as follows.

Composition of the Medium:

Sucrose 15.0% Dipotassium hydrogenphosphate 0.5% Beer yeast extract 0.2%pH 7.0

Properties and State of the Concentrate:

Appearance from light-brown to brown viscous liquid Flavor havingsour-sweet flavor and free from nasty taste and nasty smell Sugarcontent (Bx) 65° pH  5.4 Loss on drying 31.6% Fructose 42.0%Oligosaccharides* 23.2% *From the result of FIG. 1, it is surmised thatleucrose, mannitol, oligo- to poly-fructoses and dextran are contained.

Operation Condition of Liquid Chromatography (Corresponding to FIG. 1):

Sample amount: 80 μl of 2.0% by weight/volume solution

Column: G2000PW×2 (made by Toso Co.)

Eluent: 0.1M NaCl aqueous solution

Flow rate: 1.0 ml/min

Temperature: 25° C.

Pressure: 90 kg/cm²

Detector: RI×1

Chart speed: 0.5 cm/min

EXAMPLE 2 Preparation of a Concentrate of the Supernatant in the CaseWhere Molasses is Used as a Main Raw Material

Streptococcus bovis ATCC 33317 (NCDO 597) as a lactic acid bacterium wasinoculated into a medium of the following composition obtained by adding2 volumes of distilled water to 1 volume of molasses, and fermented at25° C. for 24 hours under an anaerobic condition, and then 1 volume ofethanol was added to 1 volume of the fermented broth and the supernatantwas collected. The supernatant was filtered to remove the cells, ethanolwas distilled off at about 80° C. underreduced pressure (540-580 mmHg),and concentration was carried out so that the liquid amount got to beabout {fraction (1/12)} to prepare a concentrate of the supernatant. Theproperties and state and the measured value by liquid chromatography ofthe concentrate prepared were as follows.

Composition of the Medium:

Molasses 15.0% Dipotassium hydrogenphosphate 0.1% pH 6.2

Properties and State of the Concentrate:

Appearance from light-brown to brown viscous liquid Flavor havingsour-sweet flavor and free from nasty taste and nasty smell Sugarcontent (Bx) 62° pH  5.2 Loss on drying 33.5% Fructose 39.6%Oligosaccharides 22.9%

EXAMPLE 3 Preparation of a Mixed Feed Using a Concentrate of aSupernatant as a Raw Material

One kilogram of the concentrate prepared in Example 1 was added to 9 kgof granular glucose (Glufinal, made by Nihon Shiryo Kogyo Co.) as apowdering agent, and the mixture was sufficiently mixed in a horizontalpaddle mixer for 5 minutes to prepare a mixed feed. The properties andstate of the mixed feed prepared were as follows.

Appearance light-yellow powder Flavor having sour-sweet flavor and freefrom nasty taste and nasty smell Loss on drying 9.5% Glucose 79.0%Fructose 4.0% Oligosaccharides 2.5%

EXAMPLE 4 Preparation of a Mixed Feed Using a Concentrate of aSupernatant as a Raw Material

One kilogram of the concentrate prepared in Example 2 was added to 9 kgof silicic acid (made by Wako Junyaku Kogyo Co.) as an excipient forpowdering, and the mixture was sufficiently mixed in a horizontal paddlemixer for 5 minutes to prepare a mixed feed. The properties and state ofthe mixed feed (also referred to as composition) prepared were asfollows.

Appearance light-yellow powder Flavor having sour-sweet flavor and freefrom nasty taste and nasty smell Loss on drying 9.1% Silicic acid 80.5%Fructose 4.2% Oligosaccharides 2.8%

EXAMPLE 5 Salmonella Fixation Inhibition Test on a Kind of Chicken fromwhich Eggs are Taken

Method: One-day-old white leghorns (♂) were divided into 3 groups, eachgroup consisting of 30 chickens.

1) Control group: A group to which an experimental infant chick feed isgiven until the experiment is over.

2) Composition group: A group to which the feed to which 0.3% of thecomposition of Example 3 was added is given from the hatch date to thecompletion of the experiment

3) CE agent group: A group to which CE agent* in a viable cell agent wasdissolved according to the explanatory leaflet, and 0.2 ml portions ofthe solution were compulsorily administered into the one-day-oldchickens.

* A feed obtained by culturing the contents of the cecum of a chicken

About 10⁷ cells portions of Salmonella enteritidis (Phage type 4 typeoriginating in S. enteritidis food poisoning) were orally administeredto all the chickens at one-week-old. Autopsy was made on the next day, 1week and 2 weeks after the S. enteritidis administration, and the S.enteritidis number per 1 g of the cecum contents was measured.

Result: S. enteritidis number per 1 g of the cecum contents (Table-1)

On the next day after the S. enteritidis administration, the S.enteritidis number in the composition group decreased by about 2 ordersin comparison with the control group, but statistical significantdifference was not seen.

On the 7th day after the S. enteritidis administration, the S.enteritidis number in the composition group significantly decreased incomparison with the control group.

On the 14th day after the S. enteritidis administration, the number ofS. enteritidis separated was small in all the groups.

TABLE 1 S. enteritidis number per 1 g of the cecum contents in the casewhere S. enteritidis was administered to one-week-old chicks TreatmentDays after the S. enteritidis administration method 1 day 7 days 14 daysControl group 5.20 ± 0.33^(a)) 3.86 ± 0.68 2.19 ± 0.91 (10/10)^(b))(8/10) (5/10) Composition 3.53 ± 0.80 1.42 ± 0.73* 0.49 ± 0.49 group (9/10) (3/10) (1/10) CE agent 4.63 ± 0.40 3.69 ± 0.70 1.55 ± 0.68 group(10/10) (8/10) (4/10) *P < 0.05 ^(a))Average of logarithmic value of S.enteritidis number ± standard deviation ^(b))Number of S.enteritidis-positive chickens/Number of chickens used *There is asignificant difference in 5% level of significance.

EXAMPLE 6 Salmonella Attack Test on Broilers

Method: One-day-old broilers (Arbor Acres) of 2 groups, each groupconsisting of 30 broilers, were prepared, and were divided into groupsand treated as follows.

1) Control group: A group to which a broiler feed is given until theexperiment was over.

2) Composition group: A group to which the broiler feed to which 0.3% ofthe composition of Example 3 was added is given until the experiment wasover.

In both groups, the formula feed and water were freely given fromone-day-old until 19-day-old. On the 13 days and 18 days, 10⁸ cellsportions of Salmonella enteritidis were orally administered, andrespectively on the next day, the broilers were dissected and the degreeof intestinal mucosa invasion and the pH of the cecum dung wereexamined.

Results:

1) Invasion of intestinal mucosa (Table-2)

S. enteritidis attack in the 14-day-old was 26/30 broilers (86.6%) inthe control group and 15/30 broilers (50%) in the composition group.

S. enteritidis attack the 19-day-old was 25/30 broilers (83.3%) in thecontrol group and 16/30 broilers (53.3%) in the composition group.

In both 14-day-old and 19-day-old, the composition group significantlyinhibited invasion of the intestinal mucosa by S. enteritidis incomparison with the control group.

2) pH of the cecum dung (Table-3)

In the attack of S. enteritidis in the 14-day-old, the pH was 6.5±0.3 inthe control group and 5.6±0.2 in the composition group.

In the attack of S. enteritidis in the 19-day-old, the pH was 6.6±0.5 inthe control group and 5.7±0.3 in the composition group.

In both 14-day-old and 19-day-old, the composition group significantlylowered the pH of the cecum contents in comparison with the controlgroup.

TABLE 2 Invasion of intestinal mucosa Administration group Attackbacterium 14-day-old 19-day-old Control group S. enteritidis 26/30broilers 25/30 broilers (86.6%) (83.3%) Composition S. enteritidis 15/30broilers 16/30 broilers group (50.0%) (53.3%) *P < 0.05

TABLE 3 pH of cecum contents Administration Attack group bacterium14-day-old 19-day-old Control group S. enteritidis 6.5 ± 0.3 6.6 ± 0.5Composition group S. enteritidis 5.6 ± 0.2* 5.7 ± 0.3* *P < 0.05

EXAMPLE 7 Improvement Effect of Mortality in Salmonella Attack onChickens

Method: Chickens weighing around 40 g of 3 groups, each group consistingof 45 chickens, were prepared, and were divided into groups and treatedas follows.

1) Control group: A group to which a chicken feed is given until theexperiment is over.

2) Composition group (0.1% addition): A group to which the chicken feedto which 0.1% of the composition of Example 3 was added is given untilthe experiment is over.

3) Composition group (0.3% addition): A group to which the chicken feedto which 0.3% of the composition of Example 3 was added is given untilthe experiment is over.

In all the three groups, 10 days after the initiation of the experiment,2.7×10¹¹ CFU portions of Salmonella enteritidis were orallyadministered, and 2, 4 and 6 weeks thereafter, the number of salmonellacells in the droppings was measured.

Six weeks thereafter, the mortality and the pH of the droppings (6chickens) were examined.

In all the three groups, for 6 weeks of from the initiation of theexperiment to the completion thereof, the feed and water were freelygiven.

Results:

1) Number of salmonella cells in the droppings:

The number of salmonella cells in the droppings after 6 weeks was 0.95,0.34 and 0.20×10 respectively after 2, 4 and 6 weeks of the controlgroup, 0.6, 0.29 and 0.10×10 respectively after 2, 4 and 6 weeks of thecomposition group (0.1% addition), and 0.48, 0.21 and 0.00×10respectively after 2, 4 and 6 weeks of the composition group (0.3%addition), and inhibition tendency was recognized.

2) Mortality:

The mortality after 6 weeks was 17.78% in the control group, 11.11% inthe composition group (0.1% addition), and 6.67% in the compositiongroup (0.3% addition), and inhibition tendency was recognized.

3) Droppings pH

Droppings pH after 6 weeks was 7.17 in the control group, 6.22 in thecomposition group (0.1% addition), and 6.05 in the composition group(0.3% addition), and significant difference was recognized.

TABLE 4 Number of Salmonella cells, mortality and droppings pHSalmonella cells number after 2 after 4 after 6 Mortality DroppingsTreatment method weeks weeks weeks (%) pH Control group 0.95 0.34 0.2017.78 7.17 Composition group 0.60 0.29 0.10 11.11 6.22* (0.1% addition)Composition group 0.48 0.21 0.00 6.67 6.05* (0.3% addition) *There is asignificant difference

EXAMPLE 8 Improving Effect of Mortality in Heat Stress

Method: Chickens weighing around 40 g of 3 groups, each group consistingof 45 chickens, were prepared, and were divided into groups and treatedas follows.

1) Control group: A group to which a chicken feed is given until theexperiment is over.

2) Composition group (0.1% addition): A group to which the chicken feedto which 0.1% of the composition of Example 3 was added is given untilthe experiment is over.

3) Composition group (0.3% addition): A group to which the chicken feedto which. 0.3% of the composition of Example 3 was added is given untilthe experiment is over.

In all the three groups, for 6 weeks of from the initiation of theexperiment to the completion thereof, the chickens were raised at atemperature of 40±1° C. and at a humidity of 75±5% for 12 hours of oneday, and at 24-26° C. for the remaining 12 hours.

In all the three groups, for 6 weeks of from the initiation of theexperiment to the completion thereof, the feed and water were freelygiven.

Six weeks thereafter, the mortality and the pH of the droppings (6chickens) were examined (Table-5).

Results:

1) Mortality:

The mortality after 6 weeks was 33.33% in the control group, 17.78% inthe composition group (0.1% addition), and 11.11% in the compositiongroup (0.3% addition), and inhibition tendency was recognized.

2) Droppings pH

Droppings pH after 6 weeks was 7.12 in the control group, 6.28 in thecomposition group (0.1% addition), and 6.23 in the composition group(0.3% addition), and significant difference was recognized.

TABLE 5 Mortality and droppings pH Treatment method Mortality (%)Droppings pH Control group 33.33 7.12 Composition group 17.78 6.28*(0.1% addition) Composition group 11.11 6.23* (0.3% addition) *There isa significant difference

Industrial Applicability

According to the invention, when the preparation is added in an amountof 0.01 to 10%, preferably 0.05 to 5.0% to a formula feed for animals asinfants shortly after their birth or adults, and the mixture is orallyadministered to an animal salmonella infection in the cecum dung andinvasion of the intestinal mucosa are prevented and treated, andproduction of salmonella-free stock farm products is made possible.Therefore, the invention can, for example, be utilized in the poultryindustry.

What is claimed is:
 1. A method for treating salmonellosis of poultry orlivestock which comprises administering, to an animal of poultry orlivestock, a pharmaceutically effective amount of a dextran fermentationby-product obtained by effecting fermentation with the use of at leastone strain belonging to lactic acid bacteria which is selected from thegroup consisting of the genera Leuconostoc, Streptococcus andStreptobacterium in a sucrose-containing nutrient medium.
 2. The methodaccording to claim 1, wherein the lactic acid bacterium of the genusLeuconostoc is Leuconostoc mesenteroides.
 3. The method according toclaim 1, wherein the lactic acid bacterium of the genus Streptococcus isStreptococcus bovis.
 4. The method according to claim 1, wherein thedextran fermentation by-product is combined with a granulating agent. 5.The method according to claim 1, wherein the dextran fermentationby-product is administered as a composition which comprises the dextranfermentation by-product in combination with a pharmaceutical excipientor carrier.
 6. The method according to claim 1, wherein the dextranfermentation by-product is administered as a composition which comprisesthe dextran fermentation by-product in combination with a raw materialfor feed.
 7. The method according to claim 6, wherein the content of thedextran fermentation by-product in the composition is at least 0.1% byweight based on the total weight of the composition.